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<div class="titlepage"><div><div><h5 class="title">
<a name="boost_asio.reference.use_future_t.operator_lp__rp_.overload1"></a><a class="link" href="overload1.html" title="use_future_t::operator() (1 of 2 overloads)">use_future_t::operator()
          (1 of 2 overloads)</a>
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<p>
            Wrap a function object in a packaged task.
          </p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
    <span class="keyword">typename</span> <span class="identifier">Function</span><span class="special">&gt;</span>
<span class="identifier">unspecified</span> <span class="keyword">operator</span><span class="special">()(</span>
    <span class="identifier">Function</span> <span class="special">&amp;&amp;</span> <span class="identifier">f</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
</pre>
<p>
            The <code class="computeroutput"><span class="identifier">package</span></code> function
            is used to adapt a function object as a packaged task. When this adapter
            is passed as a completion token to an asynchronous operation, the result
            of the function object is returned via a std::future.
          </p>
<h6>
<a name="boost_asio.reference.use_future_t.operator_lp__rp_.overload1.h0"></a>
            <span class="phrase"><a name="boost_asio.reference.use_future_t.operator_lp__rp_.overload1.example"></a></span><a class="link" href="overload1.html#boost_asio.reference.use_future_t.operator_lp__rp_.overload1.example">Example</a>
          </h6>
<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">future</span><span class="special">&lt;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span><span class="special">&gt;</span> <span class="identifier">fut</span> <span class="special">=</span>
  <span class="identifier">my_socket</span><span class="special">.</span><span class="identifier">async_read_some</span><span class="special">(</span><span class="identifier">buffer</span><span class="special">,</span>
    <span class="identifier">use_future</span><span class="special">([](</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span> <span class="identifier">ec</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">n</span><span class="special">)</span>
      <span class="special">{</span>
        <span class="keyword">return</span> <span class="identifier">ec</span> <span class="special">?</span> <span class="number">0</span> <span class="special">:</span> <span class="identifier">n</span><span class="special">;</span>
      <span class="special">}));</span>
<span class="special">...</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">n</span> <span class="special">=</span> <span class="identifier">fut</span><span class="special">.</span><span class="identifier">get</span><span class="special">();</span>
</pre>
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<div class="copyright-footer">Copyright © 2003-2025 Christopher M.
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        Distributed under the Boost Software License, Version 1.0. (See accompanying
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